One of the primary considerations in the design and operation of wind turbines is the noise levels produced during operation of the wind turbine. Particularly in the case of on-shore wind turbines which may be located close to inhabited areas, the noise from wind turbines can be a limiting factor when considering possible wind turbine locations. Accordingly, it is of interest to provide for wind turbine designs having reduced noise output during operation.
A large portion of the noise produced during wind turbine operation is due to turbulence formed at the trailing edge of a wind turbine blade, as the relatively faster suction-side airflow meets with the relatively slower pressure-side airflow. The relatively high level of turbulent kinetic energy in the combined airflows results in a turbulent scattering of airflow at the trailing edge, which produces scattering noise.
It is known to provide fixed serrations or bristles at the trailing edge of a wind turbine blade in order to disrupt the trailing edge airflow, thereby damping or reducing the turbulence formed at the trailing edge, and consequently the associated noise levels. Examples of trailing edge serrations can be seen in US Patent Publication No. US 2011/0142666 A1.
However, such noise-reducing features do not provide a complete elimination of trailing edge noise during blade operation.
It is an object of the invention to provide a wind turbine blade having improved noise-reducing characteristics over the known blade designs.